We are going to be in the Conwy area at the end of July. A thought was to take a two day "viator" tour of castles for orientation and then a rental car for exploring outside of Conwy the remaining three days. Thoughts from others? Thanks.
If you are renting a car for the remaining three days I would move on from Conwy and travel as you go to other locations.
You can call ahead and make reservations. Betws y coed has a more rustic location than Conwy. Or you could stay on a sheep farm on Anglesey. They are all easy drives but offer more variety then just going back to Conwy which is just a small town.
Just rent a car and tour the castles on your own. The nearby ones are Conwy, Caernarfon, and Beaumaris. One can easily spend an entire day on Anglesey alone; Llynon windmill, south stack lighthouse, ancient burial chambers and standing stones, the town with the long name (Llanfair...), Menai Bridge, and Beaumaris castle. Llandudno is nice to walk around for a couple hours. There’s the small, 6-seat St. Trillo chapel in nearby Rhos on Sea (right along the waterfront road). Portmeirion is a sight many people visit. Of course there is Snowdonia National Park.
I agree with the above about touring the castles by yourself; that's what we did and it was easy. You can get a Welsh Explorer pass at Conwy Castle to save on entries.
Viator don't run tours - they are a third party booking agent. It's easy enough to tour yourselves.
From Conwy, you could visit Snowdonia, Bodnant Gardens, the other castles of the north Wales coast such as Caernarfon, Chirk castle and the Pontcysyllte Aqueduct are about an hour away as is Chester.